F25QTZ - NUV-MAMA, Longpass

Description

The F25QTZ filter with the NUV-MAMA provides high-throughput broad-band NUV imaging with better rejection of geocoronal emission than the F25MAMA or F25SRF2 modes, the same field of view, and the same high spatial resolution.

Recommended Uses

Recommended for broad-band NUV imaging of faint targets.

Special Considerations

Sky background on the day side of the orbit contains a significant contribution from [O II] air glow emission at 2471 Å. In high-background conditions, the sky background can contribute a significant amount to the detector background. Observers can limit the background (with some cost to the total amount of observing time per orbit) by using the DARKTIME special requirement.

Pivot λ (Å)

FWHM (Å)

AB mag zero point

Speak

Bλ

R80 (arcsec)

Flux in central pixel

2359.3

998.7

23.713

1.42e+14

1099.6

0.32

8%

Figure 14.35: F25QTZ NUV-MAMA Integrated System Throughput and Redleak



Table 14.15: F25QTZ NUV-MAMA Sensitivity & Throughput

λ

Sensitivity

% Throughput

1500.

1.83E13

0.54

1600.

2.57E13

0.79

1700.

3.12E13

0.81

1800.

4.13E13

1.01

1900.

5.57E13

1.29

2000.

7.69E13

1.69

2100.

9.91E13

2.07

2200.

1.18E14

2.35

2300.

1.30E14

2.48

2400.

1.36E14

2.48

2500.

1.39E14

2.44

2600.

1.41E14

2.39

2700.

1.39E14

2.25

2800.

1.33E14

2.09

2900.

1.09E14

1.66

3000.

8.35E13

1.22

Figure 14.36: Point Source S/N vs. V+ABν for the F25QTZ NUV-MAMA mode. Top curves are for DARKTIME. Bottom curves are for average sky. Curves are labeled by required exposure time (sec.).


Figure 14.37: Extended Source S/N vs. V+ABν for the F25QTZ NUV-MAMA mode. Top curves are for an area of 0.2 arcsec2; bottom curves are for 1 arcsec2. Average sky assumed. Curves are labeled by required exposure time (seconds).



Table 14.16: Radial Profile for F25QTZ (see STIS ISR 2003-01)

Radius


 

Fraction of Energy Encircled

Pixels

Arcsec

Intensity

1

0.024

6.046e-02

0.210

1.5

0.037

4.292e-02

0.328

2

0.049

2.825e-02

0.440

3

0.073

1.036e-02

0.591

4

0.098

4.085e-03

0.667

5

0.122

1.839e-03

0.718

10

0.245

2.099e-04

0.820

15

0.367

9.929e-05

0.874

20

0.490

4.775e-05

0.911

25

0.613

2.706e-05

0.934

30

0.735

1.876e-05

0.953

40

0.980

8.441e-06

0.983

Figure 14.38: Point Source PSF for F25QTZ NUV-MAMA, 7."5 square (at pixel 606,649, log scaled). Note PSF ghost ~45 pixels left of peak pixel and a few 10-3 of the peak


Figure 14.39: Point Source Encircled Energy for F25QTZ NUV-MAMA


Figure 14.40: Point Source Intensity vs. Radius for F25QTZ NUV-MAMA